One of my biggest regrets when I became foreign secretary, in 2010, was that it was too late to save the Foreign Office library, shamefully abandoned and dismantled by my predecessors.
However digital our lives become, we need to retain a physical connection with the archives and documentation of our history. Mercifully, though, the wonderful library of my official residence, Chevening House, was part of an independent trust and beyond the reach of the fads of modernisation.
Late at night, I would wander in there to try to absorb a little bit of the wisdom of centuries. Often I would turn to an original copy of one of the most influential books of the last three hundred years: Adam Smith’s “The Wealth of Nations”.
In it, the brilliant Scottish economist laid out what we now recognise as the classic case for free trade, that if nations dropped their protective instinct for producing everything themselves, and instead did what they were best at and traded with each other, all of them could benefit. Smith’s work influenced the thinking of leaders from William Pitt to Thomas Jefferson, and has been tested and proved right countless times.
Intense British debates over tariffs in the 1840s and up to the Twenties were resolved in favour of free trade. Protectionism has been understood as exacerbating the unemployment and deprivation of the Great Depression.
A short trip around the world today would prove the point: places such as Singapore and Hong Kong have become vastly successful centres of prosperity, despite having few natural resources, through their openness to trade. The contrast with others that are resource-rich but protectionist, like Venezuela and Argentina, is stark.
Time and again, countries that have tried to protect industries behind a wall of import tariffs or subsidies have found they have simply held themselves back — Ireland until the Fifties being a case in point. In recent decades, trade has helped hundreds of millions of people, in China in particular, to escape poverty, while allowing western consumers, like us, to have the benefit of cheap goods and new technologies in abundance.
Of course, there are always specific losers from open trade, undercut by the lower costs or new designs of another country. But the historical evidence that societies become far richer as a whole when they shake off protectionism is so overwhelming that it has seemed unnecessary to argue the case for it.
That is until now. The insights of Adam Smith have not stopped being true. Yet in the rantings of Donald Trump, Bernie Sanders and some voices on this side of the Atlantic, they are being forgotten.
With global trade talks so complicated that they have been stalled for decades, most recent advances in free trade have been through bilateral or regional agreements — the most extensive being the Trans Pacific Partnership involving the US, Japan and 10 other nations.
Such deals are among the best hopes of the world steering away from a new recession, but the freer trade they would bring is now denounced in every US primary as a threat to American jobs.
Worse still, the long-held dream of the Transatlantic Trade and Investment Partnership (TTIP) is now assailed in America and being deserted by the French government as its own elections draw near. In Germany, protests greeted President Obama when he put the case for TTIP.
Even here in Britain, the centre of global finance and the ninth biggest exporter in the world, trade unions and pressure groups have turned against this new boost to transatlantic prosperity. The week brought the dismal sight of some Tory MPs forcing an amendment to the welcoming of the Queen’s Speech on the spurious grounds that TTIP is a threat to the NHS.
For the French to oppose more open trade is not so surprising. When Americans, British and Germans start opposing it, free trade is in real trouble.
Trade is becoming the scapegoat for all the pressures of rapidly changing economies, blamed for poor business practices, inequality, and the growth of corporate power. Yet these problems are not caused by trade as such, and increased barriers to it make life harder for developing countries and shield inefficient corporations behind walls for which the consumer or taxpayer has to pay.
Growing inequality in many societies is caused by many factors, including the new technologies that heavily reward those who invent and license them, and the persistence of central banks in pursuing “quantitative easing” which inflates the wealth of those with large assets.
Excessive corporate power needs to be constrained by antitrust action — Adam Smith warned against the power of monopolies just as he demonstrated the futility of protectionism.
But constraining freer trade is not the answer: it is a self-defeating diversion. Good behaviour by international companies is part of the answer to this assault.
They are under scrutiny by the public as never before, and need to show fairness to the countries they work in — including in how they pay their taxes — concern for the environment and a long-term commitment to their workforce.
Most of all, political leaders and commentators will have to explain the case for free trade all over again. TTIP is not a threat to the NHS — routine clauses prevent that.
The power it gives companies to sue governments is normal in any trade agreement that can be enforced. And although it means Europe accepting many American standards, it gives the two together the chance to set the standards of the world.
Whether we end up in or out of the EU, attitudes to free trade may come to define politics as much as old Left-Right divisions. Are Conservatives going to stick to free-market principles, or succumb with Labour to pressure-group politics?
Is Ukip going to argue for global freedom after the referendum, with its one MP, Douglas Carswell, or for fortress Britain with Nigel Farage? There are instinctive free-traders on both sides of the referendum argument.
Once it is over, they will need to work together to avoid a new age of depression, in which the whole world economy could be diminished for the sake of popular illusions.
And a good starting point would be to tiptoe into a library and study words written in the 1770s, but just as valid today.
The Telegraph Group Limited, London 2016
